Sensitization to X-rays of transforming DNA by Ag+.
A transforming DNA system has been used to study the effect of silver ion on the X-ray-induced inactivation of the functional ability to DNA. In N2 transforming DNA is sensitized to radiation by Ag+, with the maximum sensitization occurring at a ratio of one Ag+ added per DNA base. This response can be partially prevented by addition of .OH scavengers. In O2 the transforming DNA is only slightly sensitized by Ag+ except at very high Ag+ concentrations. These results are interpreted in terms of the eaq- sequestration theory of radiation sensitization. Studies on the binding of Ag+ to DNA show that at the maximum sensitization in N2, there is one Ag+ bound per DNA base pair and that this binding is unaffected by .OH scavengers, although radiation may change these binding properties. Steady-state radiation chemistry studies indicate a difference in the response of DNA-Ag+ complexes to irradiation in N2 and in O2. As with the transforming DNA studies, these can be interpreted in terms of the eaq- sequestration theory of radiation sensitization.
D000818:Animals; D001412:Bacillus subtilis / Q000528:radiation effects*; D004269:DNA, Bacterial / Q000528:radiation effects*; D009584:Nitrogen / Q000494:pharmacology; D010100:Oxygen / Q000494:pharmacology; D011838:Radiation-Sensitizing Agents; D012834:Silver / Q000494:pharmacology*
D004269:DNA, Bacterial; D011838:Radiation-Sensitizing Agents; D012834:Silver; D009584:Nitrogen; D010100:Oxygen